1. Field of the Invention
The present invention relates to a hollow golf club head.
2. Description of the Related Art
The volume of a hollow golf club head increases every year, making the crown portion and sole portion thinner but larger in area. Therefore, a low-pitched impact sound is more likely to be generated at the time of striking a golf ball. Under the circumstances, golfers who prefer high-pitched impact sounds want golf club heads that generate higher-pitched impact sounds.
As a method for improving an impact sound, Japanese Patent Laid-Open No. 2009-233266 discloses a golf club head including a rib which traverses the sole portion, side portion, and crown portion. Also, Japanese Patent Laid-Open No. 2010-35915 discloses a golf club head including a recessed portion formed in the crown portion.
The recent golf club head often has a sole portion having a shape as its design feature. Therefore, a structure for improving an impact sound has a level of freedom higher in the crown portion than in the sole portion.
However, the crown portion generally has a shape which bulges out upward, and therefore has a relatively large curvature. Therefore, an impact sound with poor resonance is more likely to be generated.